Appl. Nano, Volume 7, Issue 1 (March 2026) – 9 articles

The commercialization of V-based catalysts for the selective catalytic reduction of NOx by NH₃ (NH₃-SCR) is hindered by their narrow operating temperature window, insufficient low-temperature (LT) activity, and severe SO₂-to-SO₃ oxidation. To bridge this gap, we herein introduced Nb and hexagonal BN into a VW/TiO₂ system to simultaneously enhance its LT SCR activity, suppress undesired side reactions, and improve durability. Nb incorporation promoted V⁵⁺/V⁴⁺ redox cycling and enhanced lattice oxygen mobility, thus reducing the apparent activation energy and suppressing SO₂ oxidation at elevated temperatures. However, excessive Nb loading induced NH₃ oxidation and N₂O formation. This drawback was mitigated by introducing BN as a dispersion promoter, which helped secure high catalytic performance at a reduced Nb content. The VWNb/Ti-BN catalyst achieved superior NOx conversion and N₂ selectivity over a wide temperature range and benefited from notably suppressed NH₃ oxidation and SO₂-to-SO₃ oxidation. Kinetic analysis revealed that Nb primarily lowered the reaction energy barrier via redox property enhancement, whereas BN accelerated surface reaction turnover by stabilizing and dispersing active acidic sites, markedly increasing the turnover frequency without reducing the activation energy. In situ spectroscopic analysis confirmed the accelerated consumption of adsorbed NH₃ species and enhanced formation of reactive NOx intermediates, indicating SCR pathway enhancement. After aging in the presence of SO₂ and H₂O, the best-performing honeycomb-type monolithic catalyst retained and NOx conversion of >80%, demonstrating excellent long-term durability under practical conditions. A composition-aware machine learning model based on log-ratio-transformed variables quantitatively identified the synergistic balance among V, Nb, W, BN, and TiO₂ as the dominant factor governing LT SCR performance. Thus, this work provides valuable mechanistic insights and a strategy for designing wide-temperature-window SCR catalysts with improved activity, selectivity, and resistance to sulfur poisoning. Full article

Currently, titanium dioxide films are widely used as the electron transport layer material in perovskite solar cells. An alternative to titanium dioxide for this role could be niobium pentoxide (Nb₂O₅), an n-type conducting semiconductor oxide. However, the application of Nb₂O₅ in perovskite solar cells is hindered by a lack of data on its electron transport properties, electrophysical parameters, and current–voltage characteristics. Amorphous niobium pentoxide films were obtained by magnetron sputtering. To study their electrical and capacitive properties, a structure of heavily doped n⁺-silicon (n⁺)/niobium oxide/aluminum was used. Based on the analysis of the I–V curves, it was concluded that for a sample at 25 °C, the electron mean free path is greater than the width of the Schottky barrier layer, allowing electrons to pass through this layer without collisions. At temperatures of 35 °C and higher, electrons experience numerous collisions within the Schottky barrier layer. The height of the Schottky barrier for the contact between niobium pentoxide and aluminum was determined. The obtained capacitance frequency plots were explained using the concepts of dipole-relaxation polarization in a dielectric, where electric dipoles can reorient in an external electric field. It has been shown that the use of magnetron sputtering to produce amorphous niobium pentoxide films leads to a reduction in the effective Schottky barrier height. This allows for high electron injection density at low voltages when using such an oxide semiconductor as an electron transport layer, thereby potentially increasing the efficiency of solar cells. Full article

Amorphous calcium phosphate (ACP), a key calcium-phosphorus compound, has been widely applied in fields such as dentistry, orthopedics, and biomedicine. However, its potential for removing copper ions from aqueous solutions remains largely unexplored. In this study, sodium citrate-stabilized amorphous calcium phosphate (Cit-ACP) and its calcined derivatives at various temperatures were successfully synthesized as adsorbents for copper ions. The adsorption behavior of Cit-ACP was best described by the Langmuir isotherm, with kinetics following a pseudo-second-order model. Under conditions of pH 5.5 and an initial copper ion concentration of 200 mg/L, Cit-ACP exhibited a maximum adsorption capacity of 323.96 mg/g. Thermodynamic analysis confirmed that the adsorption process was spontaneous and endothermic. Comprehensive characterization via XRD, XPS, and zeta potential measurements before and after adsorption revealed a two-stage adsorption mechanism. At low initial copper concentrations, adsorption occurred predominantly through surface complexation between copper ions and sodium citrate molecules on Cit-ACP nanoparticles. At higher concentrations, the mechanism extended to include co-precipitation of copper ions with hydroxyl groups, which promoted the transformation of Cit-ACP into copper-substituted calcium phosphate phases, such as copper-containing hydroxyapatite. Owing to its straightforward synthesis, high adsorption capacity, and inherent biocompatibility, Cit-ACP presents a promising, cost-effective, and efficient adsorbent for the removal of copper ions from aqueous environments. Full article

The utilization of biopolymers as raw materials for the development of sustainable materials has become one of the most promising strategies to minimize the negative impact of plastic pollution. Tubers such as purple yam are rich in starch, which serves as the main component for producing strong and durable bioplastics with properties comparable to conventional plastics. In this study, purple yam flour was used as a raw material to develop a biodegradable film through the casting method. Additionally, Flour Nanoparticles (FN) extracted via the Aqueous Counter Collision technique were incorporated to enhance the mechanical, morphological, and barrier properties of the films. The nanoparticles exhibited sizes below 100 nm, as determined by DLS analysis. The casting process was carried out using film solutions containing 2 wt% flour and 15 wt% glycerol, with FN concentrations of 5 wt%, 15 wt%, and 25 wt%. The main results showed that the films with 25 wt% FN displayed improved mechanical strength, increasing from 2.2 MPa (control) to 7.3 MPa, as well as enhanced thermal resistance, rising from 68 °C (control) to 102 °C. The films also exhibited a smoother morphology, indicating improved water vapor transmission (WVT). The incorporation of FN thus contributed to the development of films with reduced hydrophobicity. Full article

Biogenic copper-based nanoparticles have attracted attention as potent antimicrobial agents synthesised via environmentally sustainable routes using plants, microorganisms, and biological waste. Green synthesis leverages phytochemicals, enzymes, and proteins as natural reducing and stabilising agents, enabling nanoparticle formation under mild, non-toxic conditions without hazardous reagents. The resulting nanoparticles are typically spherical, <100 nm in size, and enriched with bioactive surface functionalities that contribute to broad-spectrum antimicrobial activity against bacteria, fungi, and biofilms. Their antimicrobial effects arise from interconnected mechanisms, including the generation of reactive oxygen species, the release of Cu² ions, membrane disruption, and interference with vital metabolic and genetic processes. Hybrid systems such as Ag–Cu, Zn–CuO, and CuS nanoparticles further enhance efficacy through synergistic redox and photothermal effects. These properties support applications in medical coatings, wound dressings, food packaging, aquaculture disease management, and sustainable crop protection. However, toxicity is highly context-dependent, influenced by factors such as nanoparticle size, shape, surface chemistry, capping agent, concentration, exposure medium, and the biological system. Small or weakly capped NPs can induce cytotoxicity, hemolysis, developmental defects, or growth inhibition, whereas functionalization or capping can improve selectivity and biocompatibility. Standardised physicochemical characterisation, harmonised toxicity testing, and mechanistic understanding are critical for the safe translation of biogenic CuNPs into regulatory-approved applications. This review summarises recent advances (2015–2025) in the biogenic synthesis of copper-based nanoparticles, highlighting how biological systems govern nanoparticle morphology, stability, and antimicrobial efficiency. It integrates mechanistic insights, compares monometallic and hybrid systems, and evaluates emerging applications in medicine, agriculture, aquaculture, and food safety. The review also identifies current limitations and future directions for standardisation, toxicity evaluation, and regulatory approval. Full article

The interface between synthetic materials and biological systems is a critical determinant of performance in medical devices and biosensors. This review examines the evolution of biointerface science through the lens of self-assembled monolayers (SAMs) of thiols on gold, a model system that offers atomic-level control over surface chemistry. We trace the field from the foundational structural characterization to the establishment of empirical design rules for bio-inertness. While early theoretical models attributed protein resistance to steric repulsion forces in polymer brushes, contemporary understanding has shifted toward the “water barrier” hypothesis, which posits that tightly bound interfacial water prevents direct biomolecular contact. We highlight recent studies that extend these concepts into “realistic” crowded biological environments. Their work reveals that fouling surfaces in crowded media generate a “viscous interphase layer” (VIL) that extends tens of nanometers into solution, whereas zwitterionic surfaces maintain a robust hydration shell that prevents this accumulation. Furthermore, this hydration barrier is shown to fundamentally alter bacterial mechanics, forcing microorganisms into a reversible, tethered “hovering” state at a significant biological interaction distance (>100 nm) from the surface, effectively precluding biofilm nucleation. These insights underscore that the future of antifouling material design lies in the precise engineering of interfacial hydration structures. Full article

ZnO semiconductor-based photocatalysts are mainly studied for the elimination of toxic textile dyes. Metal-doped ZnO displays better performance for this purpose. Herein, Al-doped ZnO (Al–ZnO) was prepared using the mechanochemical calcination method with varying aluminum concentrations for the degradation of the persistent methylene blue (MB) dye. Various characterization techniques, including XRD, FTIR, FESEM, TEM, UV-DRS, and XPS, revealed the improved properties of 3% Al–ZnO in degrading the MB dye. It exhibits 96.56% degradation of 25 mg/L MB dye under 60 min of natural sunlight irradiation with a catalyst dose of 0.5 g/L at a natural pH of 6.4. A smaller particle size, a lower band gap energy of 3.264 eV, and the presence of oxygen vacancies and defect states all facilitate photocatalytic degradation. Radical scavenger experiments using ascorbic acid (for •O₂⁻), 2-propanol (for •OH), and diammonium oxalate (for h⁺) confirmed the crucial role of superoxide (•O₂⁻) and hydroxyl (•OH) radicals in the degradation mechanism. The achievement of 82.80% MB degradation efficiency at the 4th cycle validates the notable stability and excellent reusability of Al–ZnO. Full article

This study aims to address a major challenge and find solutions for developing less expensive, lighter, and more efficient energy storage materials while remaining environmentally friendly. This work combines the study of the structural, morphological, and optical properties of epoxy nanocomposites containing ZnO and SnO₂ and highlights the influence of oxide filler content on their energy storage performance. To this end, epoxy nanocomposites filled with metal oxides (ZnO and SnO₂) prepared by extrusion, a simple, economical, and reliable industrial method, were studied and compared. The materials obtained are inexpensive, lightweight, and highly efficient, and can replace traditional glass-based systems in the energy sector. The results of XRD, SEM, and FTIR analyses show the absence of impurities, the stability of the structures in humid environments, and the homogeneity of the prepared films. They also indicate that the nature and charge content of the oxide integrated into the polymer matrix play a significant role in the properties of the nanocomposites. Optical measurements were used to determine the film thickness, the type of electronic transition, the band gap energy, and the Urbach energy. Based on the results obtained, the prepared nanocomposite films appear to be promising materials for energy-based optical applications. Full article

Objectives: This study aimed to optimize WS6-loaded nanoparticles (NPs) with favorable therapeutic properties, including appropriate size, low toxicity, high encapsulation efficiency, and enhanced biocompatibility, for selective cancer targeting and regenerative applications. Methods: Three formulations were investigated: solid lipid nanoparticles (SLNs), polycaprolactone (PCL)-based NPs, and Eudragit RS100-based NPs via microfluidic synthesis. Their physicochemical properties were assessed, followed by biological evaluation on normal cells—dental-derived stem cells (DSCs), gingival fibroblasts (GFs), and human dermal fibroblasts (HDFs)—and cancer cell lines MDA-231 and HepG2. Assays included MTT for viability, apoptosis/necrosis, cell cycle analysis, ROS detection, and cytokine profiling. Results: SLNs showed inherent toxicity despite improved viability upon WS6 loading. PCL NPs improved encapsulation and compatibility but lacked stability. The microfluidic RS-WS6 NPs exhibited optimal characteristics, significantly enhancing viability in normal cells and selectively inducing apoptosis in cancer cells. At 1 µM, RS-WS6 NPs reduced ROS in normal cells (p < 0.05) and increased it in cancer cells (p < 0.05). Cytokine analysis revealed significant downregulation of IL-6, IL-12p70, and TNF-α (p < 0.05), indicating immunomodulatory potential. Conclusions: RS-WS6 NPs developed via microfluidics offer a promising therapeutic platform with selective cytotoxicity against cancer cells, minimal toxicity to normal cells, and anti-inflammatory properties, supporting their use in targeted therapy and regenerative medicine. Full article